Tissue ablation and/or cauterization are common techniques used for the surgical treatment of cardiac arrhythmia, such as atrial fibrillation. In general terms, cardiac arrhythmia relates to disturbances in the heart's electrical system that cause an abnormal heartbeat. Irregular heartbeats, or arrhythmia, can be caused by physiological or pathological disturbances in the discharge of electrical impulses from the sinoatrial node or in the transmission of the signal through heart tissue, or by spontaneous, unexpected electrical signals generated within the heart. One specific type of arrhythmia is atrial fibrillation, in which instead of a single beat, numerous electrical impulses are generated by depolarizing tissue at one or more locations in the atria or other locations in the heart. These unexpected electrical impulses produce irregular, often rapid heartbeats in the atria. In order to overcome this problem, ablation of the abnormal tissue or accessory pathway responsible for the atrial fibrillation can be an effective treatment. The locations of such tissue ablation can vary, depending on the particular pathway irregularities and the desired surgical outcomes to be achieved.
Regardless of the exact application, ablation or cauterization of tissue can be achieved by applying ablative energy to target tissue, which may include radiofrequency electrical energy, direct current electrical energy, and the like. In such cases, the ablative energy can be delivered by an electrode that is placed in contact with the target tissue, for example. For some treatments, the electrode can be formed as a part of a catheter that is subcutaneously delivered to the target site. However, such catheters are often designed to be able to travel long distances and through complicated pathways in a patient, and therefore can be too flexible to be able to achieve precise placement of the electrodes relative to the target tissue.
Hand-held electrosurgical systems can alternatively be used, in order to overcome disadvantages of catheter-based devices. Such electrosurgical instruments can include a hand-held instrument capable of ablating tissue or cauterizing tissue, but does not include an elongated, flexible delivery catheter. The hand-held instrument can be comparatively short to provide a more rigid attachment of the electrode tip to the instrument's handle for precise manipulation by a surgeon. The rigid construction of the electrosurgical instrument requires relatively direct, open access to the targeted tissue. Thus, for treatment of atrial fibrillation via an electrosurgical instrument, it can be desirable to gain access to the patient's heart through one or more openings in the patient's chest (such as via a sternotomy, a thoracotomy, a small incision, a port, and/or the like). In addition, the patient's heart may be opened through one or more incisions, thereby allowing access to the endocardial surface of the heart.
Once the target site (e.g., right atrium, left atrium, epicardial surface, endocardial surface, etc.) is accessible, the surgeon can position the electrode tip of the electrosurgical instrument at the target site. The tip is then energized, allowing the tip to ablate or cauterize the contacted tissue. A desired lesion pattern can then be created by moving the tip to particular locations relative to the target site. Due to the relatively short and rigid construction of many hand-held instruments described above, a surgeon can control the exact positioning and movement of the tip to achieve a desired ablation result.
With many of these hand-held electrosurgical instruments, however, a particular directional orientation is designed or chosen to achieve a certain ablation pattern. For example, the instrument can include a handle from which a rigid neck member (with a distal tip) extends with a preset curvature. This permanent curvature is provided in some cases to facilitate the particular procedure for which the electrosurgical instrument is intended, such as ablation of a desired lesion pattern. While such an approach may work well for certain patients, the same instrument may not be optimal for use to reach the same anatomical locations of other patients. In addition, instruments with such a preset configuration may only be useful in a very specific area of a patient, such that it is not useful or applicable for other areas of the patient.
As discussed above, electrosurgical instruments can be highly useful for performing a variety of surgical procedures, including surgical treatment of atrial fibrillation. However, instruments that include a permanent curve or other shape variation into the instrument itself may limit the usefulness of the device to a limited number of very specialized procedures. Therefore, there is a need to provide ablation and/or cauterization instruments that can be reconfigured and which also includes controlling features at a proximal end of the instrument to allow for control of jaws or other features that are positioned at the distal end of the device. There is also a need to control jaws of a device when accessing epicardial surfaces via a subxiphoid access approach.